Change of tube diameter distribution of single-wall carbon nanotubes induced by changing the bimetallic ratio of Ni and Y catalysts

The effect of Ni and Y concentrations in bimetallic Ni–Y catalyst on single-wall carbon nanotube (SWNT) generation is studied. When we added small amount of Y with the order of 0.1 atomic % (at%) against C, the generation rate of soot in arc discharge was enhanced by a factor of 2–3 as compared with that of only C. Addition of Ni well enhanced the generation of SWNTs. The tube diameter distribution was controlled by changing Y concentration (0–9.0 at%), but was not sensitive to Ni concentration (0.2–3.0 at%). The mean tube diameter was increased with increasing Y concentration.